18% greyscale

against a blue (my favourite colour) sky. Straight out of the camera. Just a little experiment to find out if the blue of the sky would nearly match the grey of the card.

EDIT: Further thoughts (off the top of my head as usual). Light - wave or particle? Our vision perceives colour as reflected light . . . so why is the sky blue? Short light waves (blue) scatter in the atmosphere. Long (red) light waves are deflected . . . something like that . . .

       I know I complain about unrelenting blue skies but  . . . still a favourite colour along with green, yellow, orange, red, and purple (or mauve).

       EXTRA: Again straight out of the camera but shot in shadow, I had the choice to over or under expose. What to meter?